Looper-mechanism for sewing machines



Der; 3, 1940. R. BECKER LOOPER-MECHANISM FOR SEWING MACHINES Filed April 21, 1939 2 Sheets-Sheet l De. 3 1940. R. BECKER 2,224,028

I LOOPER-MECHANISM FOR4 SEWING MACHINES Filed April 21, 1939 2 Sheets-Sheet 2 Patented Dec. k3, 1940 LOOPER-MECHANISM FOR SEWING MACHINES Rudolph Becker, North Plainleld, `N. J., assignor to The Singer Manufacturing Company. Elizabeth, N. J., a corporation of New Jersey Application Amiral, 1939, :serial Nm'fzsaon 16 Claims.

'I'his invention relates more particularly to chain-stitch sewing machine mechanisms for driving the looper element which is complementary to the usual reciprocatory eye-pointed needle in the formation of stitches. The invention contemplates the provision of a mechanism for imparting lnodding movements to a looper or threadhmanipulator while the latter, is carried about a field, so that the angular relation of the thread-manipulator to the thread is varied at diilerent times of a stitch-forming cycle, thus adapting the device to, seize, position and release the thread, or otherwise manipulate the thread, as may be desired.

l5 The invention also aims to provide a' sewingv machine looper-mechanism which is of simple construction and may be operated at high speedI retracting stroke of the looper. It is dilcult to control the'position of a slipping' loop relative to Y the needle-path, as the position of such loop'depends upon the condition or coeflicient of friction of the surface of the looper. Loopers have been formed with laterally curved blades and humps 35 or protuberances at their sides to assist inI holding back and positioning the needle-thread loop, but these devices also work on the frictional or s pdrag principle and hence .are uncertain in their operation under varying conditions. It is a well y known fact that variable atmospheric conditions affect the performance of sewing machines, some times preventing their successful operation.

To the 'attainment of the "en s in view, the llooper is preferably constructed th angularly related blade and shank portions at thefneck or juncture of which there is a needle-lop-r'etaining crease or reentrant corner. The looper-blade is thrust forwardly all the way into thie needle-loop which lodges in the neck-crease. The looper isv then caused to nutate or nod and retract with the loop 'lodged in and held spread by -the neck:

crease vironi which it doesl not slip until after it is positionedfor entry by the descending needle andinas lsafely enteredor passed by the sk needlaA whereupon the loo Y"r-beak is raisedftd Serial No. 211,345, led June 2, 1938.

release the loop preparatoryfto seizure of a new loop from the needle.

Preferably the looper or thread-manipulator is mounted on a shaft which is moved laterally of its axis in an orbit or around a field and, at the 5 same time. is librated or oscillated about its own axis to cause the thread-manipulator or looper to nod or tilt in its orbital movement and thereby change its angle relative to its direction of motion for control of the thread, as will be herein- 10 after more particularly explained.

Of the accompanying drawings, Fig. 1 is a side elevation, partlyin section, of a sewing machine embodying the invention. Fig. 2 is a horizontal section through the machine-bed showing the 15 looper-mechanism in plan. Figs. 3, 4, 5, 6, '1 and 8 are a series of views of the needle and looper of the machine at different successive stages of a stitch-forming cycle, and Fig. 9 is a top plan view ofthe looper at the position shown in Fig. '1.

VThe sewing machine frame comprises the hollow oil tight box-like bed I from one end of which rises the standard '2 carrying the overhanging bracket-arm 3 terminating at its free end in the head l in which are mounted the usual presser- 25 bar 5 and endwise reciprocatory needle-bar 8 carrying the needles 1. The bed I is closed. at the bottom by the 'plate I. .The presser-bar 5 carries the` usual presser-foot 8 with which the usual feed-dog 9 cooperates to feed the work. The 30 mechanism for operating the feed-dog 9 is not shown, as it is not part of the present invention. It may be constructed substantially in accordance with the disclosure of my copending application,

35 4 The needle-bar 6 has the vusual link II connection with the crank I I on the main shaft I2 carrying the balance wheel and belt-pulley I3.

'Ihere is journaled in the bed I, a bottom rotary shaft Il which is driven 1-to-1 from the top 4o `shaft I2 by the clip-belt I5. The shaft I4 has iixed to it an eccentric I6 and a gear I1. Also journaled in the bed I is the shaft I8 having a' `driven gear I9 xed to it and meshing l-to-l with the driving gear I1. The shaft Il has an eccen- 45 V tric bore running longitudinally through it and in this bore is journaled a shaft 20 on the rearward .end of which -is fixed a fork 2l embracing the eccentric I8 on the lower rotary shaftl Il. The forwardly projecting end of the shaft 20 has xed 50 to it the looper-carrying block 22 having sockets V23 for the removable loopers 24. While a block 22 holding two loopers 2 4 is shown, it is obvious thatanyniunberoflopers, within reason, may be accommodated in a block of appropriate width.

Each looper 24 has a bend 25, Fig. 4, separating its shank f-rom its blade portion 26 which latter is slabbed on' at 2l, Fig. 9, to provide clearance for the needle 'I to enter the thread-loop 28 on the unslabbed portion 29 of the looper-blade adjlacent the neck-crease 3U under the bend 25. The looperblade also has a beak 3i at its free end and its under edge-portion 33 forwardly of the neckcrease may be considered its chin.I

From the foregoing it will be understood that the looper-shaft 20 will be carried sidewise of itself around a circular orbit by the rotary shaft I8. Also, the looper-shaft 20 will be caused to librate or oscillate in the shaft I8 by the eccentric I6. This combined orbital and oscillatory motion of the looper-shaft 20 will cause the: beak 3I, Fig. 4, of the looper 24 to move around the eld 32 while at the same time partaking of `a nutational or nodding movement. Compare Figs. 3 and 6.

Beginning with Fig. 3, the looper advances. with its chin up, into the needle-thread loop 28, Fig. 4, which loop slips onto the thicker portion 29 of the looper-blade and finally lodges in the neckcrease 30, Fig. 5. As the looper continues its advance, the combined action of the rotary carrier-shaft I8 and eccentric I6 causes the looper to nod to the position shown in Fig; 7 where, it will be observed, the angular relation of the longitudinal axis of the looper-blade to the needle path is altered; the looper-beak 3| having more of a dip relative to the neck-crease 30 in the nodded position of the looper. From the extreme position shown in Fig. 6, the looper-'blade is retracted along the lower portion of its orbital path of movement 32 in nodded relation to the needle path, so that the needle-thread loop 28 is retained in and by the neck-crease 30 and on the thicker portion 29 of the looper-blade which holds the thread-loop 28 spread, Fig. 9, and positioned for entry by 'the descending needle 1, as is essential to the correct formation of the singlethread chain-stitch. After the needle 1 has safely entered the thread-loop 28, the looper-blade is raised to the tip end or beginning point of its orbit and its chin 33 is elevated to shed the 01d loop 28 preparatory to seizing a new one. Thus, by means of the rotary bushing I8, the axis of the rock-shaft 20, which is the axis of oscillation of the looper-carrier, is raised and lowered or moved toward and away from the plane of the throatplate 35. The timing is such that the axis of oscillation of the looper is further below the plane of the throat-plate on the advancing stroke of the looper, Fig. 3, than on the retracting stroke, Fig. 7. As a result, the present looper seizes a needle-loop, Fig. 3, then nods, Fig. 6, as the axis of oscillation is raised, to get a hold on said loop,

.and retracts, while nodded, Fig. "I, to positionsaid loop for the needle.

The needles 'I work through the usual holes 34 in the throat-plate 35 over which the cloth 36 passes.

, The box-like bed I may contain oil to oodlubricate the gears Il, I9 and eccentric I6.

I The length of the blade of the present looper is only inch and its stroke is slightly over 3A; inch. Obviously a looper of this small size, having a stroke of this short length-,may be operated at high speed, particularly where, as here, the actuating mechanism is flooded with oil.

The invention is not to be understood as limited to a single-thread chain-stitch looper-mechanism. It is useful as a thread-manipulator, wherever a thread is to be taken, positioned and released.

'I'he neck-crease 30 hereinbefore referred to is not to be construed in a limited sense, for example, as a groove having side shoulders. It is intended to cover broadly a reentrant corner of any sort and not necessarily a sharp one. 'I'he present looper does not depend upon recesses, protuberances, or swelling surfaces of any sort for its successful operation.

Having thus set forth the nature of the invention what I claim herein is: v

l. In a chain-stitch sewing machine having a reciprocating eye-pointed needle, a looper formed with a blade having a loop-seizing beak, means to move said looper in an orbit about a eld parallel ment so that the looper-blade stands more nearly normal to the needle when advancing through a needle-loop than when retracting and positioning the seized loop relatively. to the descending needle.

'2. In a sewing machine, the combination with a reciprocatory eye-pointed needle, of a looper having a loop-seizing beak, and means to impart loop-seizing and loop-shedding movements to said looper around a eld parallel to said needle, while so oscillating the looper in the plane of said field as to give the looper a nodding component of motion.

3. A looper-mechanism for cooperation with the reciprocatory eye-pointed needle of a chainstitch sewing machine comprising, a looper, a looper-carrying shaft, and means to bodily move said shaft sidewise around a eld while oscillating said shaft on its own longitudinal axis.

4. A thread-manipulator mechanism for sewing machines comprising, a. rotary member, an oscillatory shaft carried by said rotary member eccentrically of and parallel to the axis of rotation of the latter, means to drive said rotary member, means to oscillate said shaft, and a threadtaker and -releaser mounted on said shaft.

-5. .A chain-stitch sewing machine loopermechanism comprising, a frame, a rotary shaft journaled therein, an eccentric'carried by said shaft, a rotary bushing journaled in said frame and geared to be driven by said shaft, a loopershaft journaled eccentrically in saidbushing, a fork ilxed to said looper-shaft and embracing said eccentric, and a looper mounted on said loopershaft.

6. A mechanical movement for a sewing machine thread-manipulator comprising, a driving shaft, an eccentric xed thereon, an eccentric bushing geared to be' driven by said driving shaft, a second shaft journaled in said bushing, a followerv arm embracing said eccentric and connected to oscillate said second shaft, and threadtaking and -releasing means carried by said second shaft for nodding movements about a field.

'7. In a sewing machine, a frame, a closed lubricant-chamber supported thereby, an actuating shaft extending through at least one wall of said chamber, mechanism disposed within said chamber and actuated by said shaft, a second shaft located in saidchamber and extending through at least one wall of said chamber and adapted to be actuated by mechanism within said chamber, and a third shaft journaled eccentrically in said second shaft and actuated by mechanism also within said lubricant-chamber.

8. In a sewing machine, a shaft, means to move said shaft laterally of its axis about a field, means to impart movements of oscillation to said shaft while the latter is being carried around said field,

p 2,224,028 and a needle-thread loop-taker carried by said shaft.

9. For use in a sewing machine having a reciprocatory needle, a looper having'a shank and a loop-taking blade thicker at one end where it joinssaid shank to spread the seized needlethread loop, said looper also having a loop-retaining reentrant corner at its under side adjacent the juncture of its blade and shank to retain the needle-thread loop on the thicker portion of the looper-blade as the latter is retracted to position the needle-thread loop relative to the descending needle. Y.

10. A chain-stitch sewing machine looper comprising. a rod bent between its ends and having a neck-crease at its under side adjacent said bend, one leg of said bent rod being slabbed off at one side adjacent said neck-crease and pointed at its end to form a loop-taking blade,r there being a thicker needle-loop-spreading portion between said slabbed off blade-portion and said neckcrease.

l1. For use in a chain-stitch sewing machine having a needle, a looper comprising a rod bent between its ends and having a neck-crease at its under side adjacent said bend, one leg of said bent rod being slabbed oi at one side adjacent said neck-crease and pointed at its end to form a loop-taking blade, there being a thicker needleloop-spreading portion between said slabbed off blade-portion and said neck-crease and means to move said looper-blade endwise into a needleloop far enough for such loop to slip onto the thicker loop-spreading portion of the looperblade and into said neck-crease where the loop is retained'during the retracting stroke of the looper until the needle-point passes the limbs of the needle-loop.

12. For complemental use with a reciprocatory needle in asewing machine, a looper, means to move said looper in an orbit which, viewed in a direction normal to the needle-path, encloses a iield,` and means to nod the looper in its orbital movement.

13. In a chain-stitch sewing machine having a reciprocatory eye-pointed needle, a looper, a looper-support, means to oscillate said looper-support about an axis, and means to bodily move said looper-support and its axis of oscillation around a field.

14. In a chain-stitch sewing machine, a frame, a rotary' bushing journaled in said frame and having an eccentric bore, a looper-supporting shaft'journaled in said bore, a looper carried by said shaft, means to oscillate said shaft in said bushing, and means -to rotate said bushing.V

said oscillatory looper-carrier whereby the axis of oscillation of the latter may be moved toward and away from the level of the throat-plate, and means to move said looper-carrier support so that the axis of oscillation of the looper-carrier is further below the level of the throat-plate on the advancing stroke of the looper'than on the re said axis will be positioned higher in the retracting stroke of the looper when the needle is taking a thread-loop on the looper.

RUDOLPH BECKER. 

